(a) Field of the Invention
The present invention relates to a dual oil feed structure having two oil holes for use in a cylinder de-activation engine for a vehicle.
(b) Description
In a conventional cylinder head of an internal combustion engine having a stationary valve lift mechanism, operation of an oil pump rotor driven by a crankshaft forms oil pressure, which in turn supplies oil to a cylinder head through a cylinder block.
FIG. 1 shows oil circuits of a conventional cylinder head of an engine having a stationary valve lift mechanism.
Referring to FIG. 1, oil pressurized by an oil pump is delivered through an oil gallery 1 of a cylinder block, thereby lubricating a crankshaft bearing and a connecting rod bearing part, and is then transferred to a cylinder head via a non-return valve which is called a check valve 2.
Thereafter, the oil transferred to the cylinder head is supplied to a hydraulic lash adjuster (HLA) 3, and at the same time is supplied to a camshaft bearing part 4.
The hydraulic lash adjuster as shown in FIG. 2 is provided with one oil hole 10 for supplying oil.
A conventional lubrication structure of a cylinder head as described above is generally applied to an engine provided with a mechanical lash adjuster (MLA) as well as an engine provided with an HLA.
However, such conventional oil circuit structure having one oil hole can be applied to a cylinder head with a stationary valve lift mechanism, but it cannot be applied to a cylinder de-activation device which adjusts a valve lift to zero position during the operation of the engine so as to stop operation of a valve, thereby deactivating operation of a cylinder.
In order to operate the cylinder de-activation device, oil circuit of the cylinder head should adequately supply or cut oil in response to the degree of necessity. Conventional oil feed structures, however, cannot satisfy such requirements, thereby not being able to stably operate the cylinder de-activation device.
There is thus a need for an improved dual oil feed structure that can satisfy the requirements so as to stably supply oil to a cylinder de-activation device.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.